<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
    <title>Three.js - Fog w/GUI</title>
    <style>
    html, body {
        height: 100%;
        margin: 0;
    }
    #c {
        width: 100%;
        height: 100%;
        display: block;
    }
    </style>
  </head>
  <body>
    <canvas id="c"></canvas>
  </body>
<!-- Import maps polyfill -->
<!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>

<script type="importmap">
{
  "imports": {
    "three": "../../build/three.module.js",
    "three/addons/": "../../examples/jsm/"
  }
}
</script>

<script type="module">
import * as THREE from 'three';
import {GUI} from 'three/addons/libs/lil-gui.module.min.js';

function main() {
  const canvas = document.querySelector('#c');
  const renderer = new THREE.WebGLRenderer({canvas});
  const gui = new GUI();

  const fov = 75;
  const aspect = 2;  // the canvas default
  const near = 0.1;
  const far = 5;
  const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
  camera.position.z = 2;

  const scene = new THREE.Scene();

  // We use this class to pass to lil-gui
  // so when it manipulates near or far
  // near is never > far and far is never < near
  // Also when lil-gui maniplates color we'll
  // update both the fog and background colors.
  class FogGUIHelper {
    constructor(fog, backgroundColor) {
      this.fog = fog;
      this.backgroundColor = backgroundColor;
    }
    get near() {
      return this.fog.near;
    }
    set near(v) {
      this.fog.near = v;
      this.fog.far = Math.max(this.fog.far, v);
    }
    get far() {
      return this.fog.far;
    }
    set far(v) {
      this.fog.far = v;
      this.fog.near = Math.min(this.fog.near, v);
    }
    get color() {
      return `#${this.fog.color.getHexString()}`;
    }
    set color(hexString) {
      this.fog.color.set(hexString);
      this.backgroundColor.set(hexString);
    }
  }

  {
    const near = 1;
    const far = 2;
    const color = 'lightblue';
    scene.fog = new THREE.Fog(color, near, far);
    scene.background = new THREE.Color(color);

    const fogGUIHelper = new FogGUIHelper(scene.fog, scene.background);
    gui.add(fogGUIHelper, 'near', near, far).listen();
    gui.add(fogGUIHelper, 'far', near, far).listen();
    gui.addColor(fogGUIHelper, 'color');
  }

  {
    const color = 0xFFFFFF;
    const intensity = 1;
    const light = new THREE.DirectionalLight(color, intensity);
    light.position.set(-1, 2, 4);
    scene.add(light);
  }

  const boxWidth = 1;
  const boxHeight = 1;
  const boxDepth = 1;
  const geometry = new THREE.BoxGeometry(boxWidth, boxHeight, boxDepth);

  function makeInstance(geometry, color, x) {
    const material = new THREE.MeshPhongMaterial({color});

    const cube = new THREE.Mesh(geometry, material);
    scene.add(cube);

    cube.position.x = x;

    return cube;
  }

  const cubes = [
    makeInstance(geometry, 0x44aa88,  0),
    makeInstance(geometry, 0x8844aa, -2),
    makeInstance(geometry, 0xaa8844,  2),
  ];

  function resizeRendererToDisplaySize(renderer) {
    const canvas = renderer.domElement;
    const width = canvas.clientWidth;
    const height = canvas.clientHeight;
    const needResize = canvas.width !== width || canvas.height !== height;
    if (needResize) {
      renderer.setSize(width, height, false);
    }
    return needResize;
  }

  function render(time) {
    time *= 0.001;

    if (resizeRendererToDisplaySize(renderer)) {
      const canvas = renderer.domElement;
      camera.aspect = canvas.clientWidth / canvas.clientHeight;
      camera.updateProjectionMatrix();
    }

    cubes.forEach((cube, ndx) => {
      const speed = 1 + ndx * .1;
      const rot = time * speed;
      cube.rotation.x = rot;
      cube.rotation.y = rot;
    });

    renderer.render(scene, camera);

    requestAnimationFrame(render);
  }

  requestAnimationFrame(render);
}

main();
</script>
</html>

